A liquid crystal polymer (a thermotropic liquid crystal polymer) has a rigid backbone in its molecule and forms liquid crystals in a molten state. It can be easily aligned under a shear force upon molding so as to give a molded article having a high strength, a high modulus, an excellent impact resistance and a small coefficient of linear expansion.
Thus, attempts have been frequently made to blend such a liquid crystal polymer with a non-liquid crystal polymer to thereby improve the properties of said non-liquid crystal polymer by taking advantage of the aforesaid excellent characteristics of the liquid crystal polymer.
For example, C. Kiss et al. [Polymer Engineering & Science, 27, 410 (1987)] reports that a liquid crystal polymer blended with a common engineering plastic and molded would be dispersed in such a manner as to form fibrils and thus exert a reinforcing effect to thereby enhance the modulus. And, T. S. Chung [Plastic Engineering, 39 (1987)] reports that a molded article produced by blending Nylon 12 with a liquid crystal polymer and molding has a small coefficient of linear expansion.
Further, U.S. Pat. Nos. 4,451,611 and 4,489,190 each shows that blending a wholly aromatic liquid crystal polyester with a polyalkylen terephtarate improves in its mechanical properties.
Furthermore, U.S. Pat. No. 4,386,174 discloses that the flowability of a non-liquid crystal polymer can be improved by blending a liquid crystal polymer therewith.
Although a molded article produced by blending a non-liquid crystal polymer with a liquid crystal polymer has an improved flowability, it suffers from such disadvantages that the excessively low melt viscosity thereof cannot give a shear stress sufficient for the alignment of the liquid crystal polymer and that the alignment, once achieved, undergoes relaxation before the completion of the cooling and solidifying, which deteriorates the reinforcing effect. In addition, the excessively low melt viscosity makes extrusion difficult.